JP2003-166508A discloses a fluid pressure cylinder in which a head-side passage allowing communication between a head-side chamber and a working fluid pressure source and a bottom-side passage allowing communication between a bottom-side chamber and the working fluid pressure source are provided in a piston rod.
The head-side passage and the bottom-side passage are respectively defined by two shaft holes formed in the solid piston rod. These two shaft holes are formed by inserting cutting tools (drills) through a tip surface of the piston rod to be located in the bottom-side chamber.
The head-side passage is a passage allowing communication between the working fluid pressure source and the head-side chamber and needs to be sealed so as not to communicate with the bottom-side chamber. Thus, a sealing member such as a plug is embedded at an opening end of the shaft hole (head-side shaft hole) defining the head-side passage and open to the bottom-side chamber.